Meteorology · Waves — Significant Wave Height
When a marine forecast gives a wave height, the term 'significant wave height' refers to:
- AThe average height of the highest one-third of the waves, approximating what an experienced observer reports✓ Correct
- BThe single largest wave expected
- CThe average of all waves including the smallest ripples
- DThe wavelength of the dominant swell
Explanation
Significant wave height (Hs) is the mean height of the highest one-third of waves. Mariners should remember that individual waves can be considerably higher — the maximum may be roughly 1.5–2 times Hs — so the occasional wave well exceeds the forecast figure.
Authority: WMO; Bowditch (Pub. No. 9), wave statistics
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